Gun with a floating breech bolt



June 3, 1969 B. clvoLANl 3,447,417

GUN WITH A FLOATING BREECH BOLT Filed Feb. 27. 1967 I IIIIIAVIIII INVENTOR BRUNO CIVOLA Nl United States Patent O 3,447,417 GUN WITH A FLOATINGBREECH BOLT Bruno Civolani, Bologna, Italy, assignor to Benelli S.p.A.Divisione Armi, Viale Mameli, Italy, a corporation of Ital y Filed Feb.27, 1967, Ser. No. 618,595 Claims priority, application Italy, Mar. 9,1966, 5,172/ 66 Int. Cl. F41d 3/04 U.S. Cl. 89--182 1 Claim ABSTRACT F'I'HE DISCLOSURE This invention relates to sporting guns and gunsgenerally and relates more particularly to a special breech boltarrangement in such guns.

The prior art fixed barrel guns have the disadvantage that prior tofiring it is required to effect a manual adjustment of the gun which isnecessary for prearranging 1t to stand the pressure which will begenerated by the cartridge during explosion in order not to damage thebreech frame duringrecoil and to facilitate the ejection of thecartridge case.

It is an object of this invention to obviate said disadvantage byproviding a weapon by which it is possible to re safely and repeatedlyany light charge or heavy charge cartridge with excellent results, Iwitha substantial reduction in recoil with respect to other guns and with aregular and easy ejection of the cartridge lease.

More particularly, the gun according to the invention is characterizedin that it has the bolt head separated from the breech bolt with aspring loosely interposed therebetween.

The spring should be suitably designed to perform the followingfunctions:

(a) to make the kick between the breech bolt mass and the bolt headelastic thus ydampening the recoil;

(b) to automatically adjust the unlocking of the locking system byproviding a more or less long unlocking delay time in relation to thedifferent pressures generated by cartridges having different charges.;

(c) to cause by its reaction the back movement of the whole breechbolt-bolt head system, enabling the eiection of the cartridge case andthe subsequent reloading of the gun.

The invention will be more fully understood from the following detaileddescription, given merely by way of example and therefore in no limitingsense, of an embodiment thereof, referring to the accompanying drawing,in which:

FIG. l shows in a perspective view, partially in section, the portion ofa sporting gun concerning this invention, with the breech bolt ready foriirng;

F'IG. 2 shows in a perspective view, partially in section, the portionof a sporting gun concerning this invention 3,447,417 Patented June 3,1969 showing the relative positions between the breech bolt and bolthead due to the reaction to firing, and

FIG. 3 shows in a perspective view, partially in section, the portion ofa sporting gun concerning this invention, with the breech bolt in thebolt head unlocking and recoil stage.

Referring first to FIG. l, a breech frame 7 is shown containing a bolthead 1 and a breech bolt 9 between which a helical spring 10 is looselyinterposed. The bolt head 1 and the breech bolt 9 have an axial bore 12,13 respectively for providing a passage for the striker 14. The bolthead 1 has a recess 15 having a rounded end, in which a correspondinglyrounded end 4 of a nib 3 seatingly engages. The latter ends at the otherend with a foot 5 having four -flat faces 16, 17, 18 and 19, whosefunction will be explained hereinafter. The face 16 is adapted tocooperate with a ramp 6 in the breech frame 7, the face 17 is adapted tocooperate with a fface 20 in a cavity 21 in the lower portion of thebreech bolt 9, the face 18 is adapted to cooperate with a fa'ce 22 inthe cavity 21 of the breech bolt 9 and the face 19 is adapted tocooperate with a face 8 in the cavity 21 of the breech bolt 9. Thetiring hammer is shown at 23 and the cartridge chamber at 24.

In the position shown the bolt head 1 locks a cartridge 2 in thecartridge chamber 24 by means of the nib 3 acting as a push rod whichengages at its rounded end 4 the corresponding rounded portion in therecess 15 and at its other end, by means of the face 16 engaging theramp 6 in the breech frame. The gun is thus ready for firing.

After tiring, see RIG. 2, the whole gun recoils because of the pressuregenerated by the charge in the cartridge 2, the breech `frame 7undergoes a sudden back movement whereas the mass of the mobile breechbolt 9, since it is not integral with the gun, opposes the shot by meansof a kick causing the spring 10 to be compressed, thus dampening anddelaying for a more or less long time depending upon the pressure of thecartridge charge, the recoil of the whole locking system. iDuring thisstage the foot 5 of the nib 3 steadily contacts the ramp 6 in the breechframe 7 and is held in this position by the engagement of its face 19with the face 8 in the cavity 21 of the breech bolt. As a result thebolt head is held locked against the cartridge chamber 24, as can beseen from FIG. 2.

After the spring 10 is compressed, to a predetermined degree because ofthe relative movement in opposite directions between the mobile breechbolt 9 and the bolt head 1 during the recoil of the whole gun, thespring, in the recoil subsiding stage, moves the breech bolt 9rearwardly. During such movement, the face 22 strikes the falce 18 onthe foot 5 of the nib 3 causing the face 16 to slide over the ramp 6 inthe breech frame 6 until the face 17 on the foot 5 engages the face 20'of the breech bolt 9 (see FIG. 3) thus releasing the nib 3 from itsengagement with the breech frame 7. The bolt head 1, because partly ofthe remaining recoil action and partly of the discharge gases, followsthe breech bolt 9 in its back movement until the mobile breech bolt andbolt head assembly strikes against the rear portion of the breech frame7 enabling a regular and easy ejection of the cartridge case.

While but one embodiment of the invention has been shown, it is obviousthat a number of changes and modifications can be made. In particular,While the invention has been illustrated and described in itsapplication to a sporting gun, it can nd application also in guns forarmed forces.

I claim:

1. In a gun of the fixed barrel type, a breech frame having a firingchamber, a bolt head -within the frame, one end of said head closingsaid chamber and said end having a recess formed therein, said bolt headbeing formed with a cylindrical extension having a passage therethrough,a ring pin in said passage, a oating breech bolt slidably mounted withinsaid 'frame and having a sleeve-like portion receiving the cylindricalextension of said bolt head and having also a passage aligned with saidfirst named passage for receiving said ring pin, an inclined abutmentformed on said breech frame, a locking nib within said frame having oneend extending into the recess in the bolt head and the other endengaging said abutment to lock said bolt head in a forward ringposition, and a spring interposed between said cylindrical extension andsaid breech bolt, said breech bolt and bolt head being relativelymovable in opposite directions at firing of the gun due to recoil forcesand the inertia of said breech bolt to compress said spring, the latterthereafter expanding during subsiding of the recoil forces to move saidbreech bolt in the opposite direction, and cooperating means on saidbreech bolt and said other end of the locking nib to release engagementbetween said other end of the nib and said inclined abutment to unlocksaid bolt head.

References Cited UNITED STATES PATENTS 676,094 6/ 1901 Linville et al.1,109,910 9/1914 Eastwiek 89--182 X 2,365,389 12/1944 Browning 89-190 X2,866,387 12/1958 Stern et al 89-190 X 2,890,626 6/1959 Amsler 89-180FOREIGN PATENTS 511,084 8/ 1939 Great Britain. 429,241 1/1948 Italy.

BENJAMIN A. BORCHELT, Primary Examiner.

STEPHEN C. BENTLEY, Assistant Examiner.

U.S. Cl. X.R. 89-190

